Trentino (an Italian Province located in the northern part of the country) is equipped with a management system of municipal solid waste collection at the forefront. Among the most positive aspects, there is a great ability for waste separation at the source and a consequent low production of residual municipal solid waste for disposal. Latest data show a gross efficiency of selective collection that has recently reached 80%, one of the highest values in Italy. This study analyzed the "Trentino system" to identify the main elements that have been at the base of the current efficient model. This provided an opportunity to propose a selective collection quality index (SCQI), including collection efficiency for each fraction, method of collection, quality of the collected materials, presence of the punctual tariff and tourist incidence. A period relevant for the transition of the collection system to the recent one was chosen for the demonstrative adoption of the proposed indicators in order to determine the potential of the index adoption. Results of the analysis of this case study were obtained in a quantitative form thanks to the sub-parameters that characterize the proposed index. This allowed selected collection decision makers to focus intently on a territory to find criticalities to be solved. For instance, the use of the index and its sub-indicators in the case of Trentino identified and comparatively quantified the local problems resulting from the presence of a large museum in a small town, tourism peaks in some valleys, and a delay in the punctual tariff adoption. The index has been proposed with the aim to make available an integrated tool to analyze other areas in Italy and abroad.